Production of electro-optical systems requires modulating input light in order to selectively enhance and filter areas of an image. For example, a bright light source may wash out the image from an image intensifier tube, resulting in an image with little or no detail. Or, a bright source may wash out the portion of the area around the bright source, again causing the image to lose detail around the source. Known methods of modulating light have not been completely satisfactory at addressing this problem.
Known methods of modulating light include the mechanical chopper, electro-optical, acousto-optical, and gated system methods for accommodating bright light sources. Mechanical choppers utilize electrically-controlled mechanical means, for example, an aperature, to modulate light. Electro-optical modulation uses electrical means to control the refractive index of a crystal in order to modulate the amount of light that passes through the crystal. Similarly, acousto-optical modulation uses force applied to a crystal to modulate the amount of light that passes through the crystal. Gated systems switch an image intensifier tube on and off in order to accommodate bright sources. These known methods, however, are not detector oriented, and cannot modulate light in response to input light. Moreover, these methods often fail to produce sufficiently clear images because they often darken the whole image, causing the darker areas of the image to become less visible.
While these methods and systems have provided a significant improvement over prior approaches, the challenges in the field of electro-optical systems have continued to increase with demands for more and better techniques having greater effectiveness. Therefore, a need has arisen for a new method and system for modulating light.